Local 302 union workers rejected a new contract Monday, setting in motion a strike first thing Tuesday morning.
According to the International Union of Operating Engineers (I.U.O.E.) Local 302, the majority of the union's membership rejected the contract up for a vote.
All union members under the Western Washington Master Labor Agreement began their strike at 6 a.m., this includes some crane operators.
"You are to exit the job on your last shift, and it is imperative that all Local 302 hands comply with all safety protocols with regard to equipment and job site maintenance," the union's website stated Monday evening. "Do not leave any job site before all safety protocols have been executed."
The strike comes as Seattle leads the nation in the number of construction cranes in the air. Many of those cranes ground to a halt Tuesday.
WATCH: Creating Seattle's skyline
Members working under the Western Washington Master Labor Agreement were asked to report to the Bothell Hall on Tuesday. Members working in District 3 and 4 were asked to report at Silverdale and Ellensburg Halls on Wednesday at 8 a.m.
Leadership for Associated General Contractors of Washington expressed disappointed at the strike.
"Throughout the bargaining process, AGC of Washington has committed to bargaining in good faith with a goal to reach a ratified agreement," they wrote in a statement posted online.
IOUE 302 did not return repeated request for comment, so it's unclear where the sticking point of negotiations is. AGC Washington declined interviews beyond its posted statement.
